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    Power

    Solar Panel Power Estimator

    Electrical output of a spacecraft solar array anywhere in the Solar System, including ageing.

    P = S₀/d² · A · η · cos θ · (1 − D)ᵗ

    Inputs

    %
    %
    years

    Results

    Electrical power
    4,083 W
    Solar irradiance at this distance
    1,361 W/m²
    Fraction of output at 1 AU
    100 %
    Worked solution
    1. S = 1361 / 1² = 1,361 W/m²
    2. P = S × A × η × cos θ × (1 − D)^t = 4,083 W

    How the result changes

    Power (W) plotted against Distance (AU), from one quarter to four times your input, with your input marked.020,00040,00060,0001234Distance (AU)Power (W)your input
    Power vs distance

    How it works

    Sunlight weakens with the square of distance: at Jupiter a panel receives only about 3.7% of the light it gets at Earth. NASA's Juno carries three large arrays with a total area of about 60 m² to work there.

    Variables

    • S₀ — solar constant, 1361 W/m² at 1 AU
    • d — distance from the Sun in AU
    • A, η — array area and cell efficiency
    • θ — angle between the Sun and the panel normal
    • D, t — annual degradation and mission age in years

    Assumptions and limits

    • Inverse-square solar flux; ignores eclipses, temperature effects and pointing losses beyond cos θ
    • Constant fractional degradation per year
    • Not valid very close to the Sun where cells overheat

    For education only. These models are simplified and are not suitable for spacecraft navigation or safety-critical engineering. See our scientific accuracy policy.